Railway stations

[AndrewIrvine]

FM radio signals can travel for miles around if nothing is in the way, but get almost stopped by a brick wall on site. I used to work in a shopping centre, I struggled to hear people in certain areas of the site, but could hear the place from 25 miles away on the Isle of Arran. One of the worst blind spots was right under the antenna, which was on the roof, while transmitting on the shopping centre floor.

[merlin100]

Some of the local sites are supposed to be using 'down fire' aerials to keep the signal from radiating too far, that includes the local ones we listen to.

[AndrewIrvine]

Anybody know what system Virgin use?

I can decode D-Star, NXDN4800, NXDN9600, DMR MotoTRBO, P-25 Phase 1, X2 TDMA and Provoice.

They use these, but I can't find which method of transmission they use. http://teleque.co.uk/#/default

[bigboyblue]

sounds like its analogue from their product sheet, in the 863-865 range. 'licence free - so radio mic range.

Channel Frequency LCD Text Channel Code
863.050 MHz Platform 1 A01
863.700 MHz Platform 2 A02
864.175 MHz Platform 3 A03
864.500 MHz Platform 4 A04
864.925 MHz Platform 5 A05
863.350 MHz Platform 6 A06
863.900 MHz Platform 7 A07
864.375 MHz Platform 8 A08
864.700 MHz Platform 9 A09
863.550 MHz Platform 10 A10

uses a funky ctcss to stop people doing their own announcements

[AndrewIrvine]

Cheers for that. I had a quick look through the site but didn't see anything, although to a point I don't need to programme them in if you can hear it anyway.

I know the likes of Carlisle still uses 453.550, just not sure of the colour code or talk group.

[G4RMT]

32.718Hz is rather low but using this band seems foolhardy. Just think what you could do with a standard radio mic pack and an iPod. You could leave the deviation set, and simply under drive it, creating your audio file with the correct sub-audible tone generated in a DAW. The fun of strange announcements, and a mobile phone to record the chaos - and in a totally unlicensed and uncontrolled band, totally legal too! Sending 500 people to the wrong platform and then back again would look great on TV. Or is this just rather childish?

[AndrewIrvine]

Where is the 32.718Hz mentioned?

[G4RMT]

See the posts from Andrew and Big Boy above - if you visit the website link, you can find the technical spec and the low tone is the 'funky one' mentioned above - which is totally non standard.

[Adrian_NR30]

Reading specs in the receiver & transmitter documentation on the teleque website, am I right that it uses 32.718 kHz as the pilot tone, not 32.718 Hz?

[m0lsx]

The pilot tone is not like a tone burst, it is a frequency that the receiver looks for to confirm the transmitter is working. If it does not hear the right tone on the right frequency the receiver goes off line.
So yes it's KHz & not Hz & it's common on professional audio equipment. G4RMT can probably tell you more about it, if you are interested.